Underreamer.



P. H. MACK.

UNDBRREAMER.

APPLwATIoN FILED nno.1o.19o9.

Patented Jan. 24, 1911.

n. .Li/4

L En UNITED STATES PATENT OFFICE.

PATRICK H. MACK, F BRADFORD, PENNSYLVANIA, ASSIGNOR TO OIL WELL SUPPLY COMPANY, OIF PITTSBURG, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

UNDERREAMER.

Specification of Letters Patent. Patented Jan. 24, 1911;

Application led December 10, ,1909. Serial No. 532,387.

To all whom 'it may concern:

Be it known-that I,PATRICK t H. MACK, a citizen of `the United States,

residing at nfradford, in the county of McKean and of that class of devices'used indrilling oil and Artesian wells, commonly termed'underreamers, having for their purpose the enlargement of the diameter of the y,well to accommodate the casing. -Tools of this class are introduced and vwithdrawn through the casing and the cutters or bits thereof are necessarily collapsible to facilitate the passage of the underreamer through the casing. Generally considered tie combining elements of all underreamers comprise a stock orvmandrel, cutters or bits movable with relation to the stock, and means for main-I taining the bits expanded and in operative relation with the stock.

Of -the two revailing types of underreamer classifiedp as above, the sliding connection between the stock and bits in one-type is effected by means of dovetailedv ways. and in the other type by a socket in the stock for the reception of the tangs ofthe bits, and in .both types the bits are suitably connected with a spring which maintains "the bits in their expanded and oper tiveposition.

My invention Vrelates ,more especially to that type wherein the stocker mandrel is socketedfor the reception and control of the tangs of the movable bits, and has for lts olo-v jects such a construction of the stock as Wlll facilitate and cheapen its production without weakening or complicating the struci ture, and also the provlsion of such a oo nnection between the spring and bits as will facilitate the yassembllng of the combining elements as well as the removal of the bits when desired. To. effect the first of said purposes I form the stock with a straight or through slot which leaves the distance block, or ortion of the stock which maintains the its in their expanded or operative position, as an integral part of the stock, and

I insert in said slot a separate socket memf ber which constitutes the socket for the reception of the tangs ofv the bits, and such a construction embodies one feature of my invention. To effect the second of said pur poses, I interpose between the bits and the spring whichactuates the bits pivoted hooks for detachably connecting said bits and spring, and such a construction embodies a second feature of my invention.

There are other, minor, features of invention, -embracin particular combinations yand features of e emental construction, all

as willhereinafter more fully appear.

In the drawings chosen for the purpose of illustrating my invention, the scope whereof is pointed out in the claims, Figure lis a longitudinal central section of an underreamer embodying my invention, the bits being shown as in the expanded or operative position. Fig. 2 is a sectional view similar to Figi 1,'w1th the bits in collapsed position to permit of the underreamer being passed through the casing. Fig. 3 is a view,

-1n elevation, of the lower end of the underreamer stock and the bits, showing the character of the abutments at the lower end of the stock, and theenga ement of the shoulders of the bits therewit Fig. 4 is a transverse section of the underreamer taken on the laneof the line 1r-4, Fig. 2.' Fig. 5

end of the stock taken on the' 'plane of the line 5-5," Fig. 4.-, the bits omitted. Fig. (jiis a detached perspective view of the socket block of the underreamer. view showing a means for compressing the' actuating spring for the bits at such times as the bits are to be appliedk to or removed from the stock.

Like symbols refer to like parts wherever they occur. y

-I will now proceed to describe my invention more fully so that ,others skilled in the art to which it appertains may apply the same.

In the'drawings, A indicates the stock and B, B the bits of an underreamer.

The stock A has just above its lower end a transverse slot 'a which is of rectangular form, `extends entirely through the stock, and

Aconstitutes the bit chamber of the stock.'.

Fig. 7 is .a detail v 'is a ongitudinal central section of the lower the bits in their expandedor operative position, and which is integral with the stock.

a2 indicates a central bore for the reception of a spring actuated rod C with which the bits B, B are connected, said bore provided with a shoulder or seat an8 for the lower end of a rod actuating spring D. The upper end of the stock A is enlarged in diameter and threaded as at a to constitute the box whereby the stock A is secured tothe pin s of the usual hub S employed for connecting theunderreamer with the drill rod or tube. f y l A :Where the bore a2 of the stock enters the transverse slot a of the stock it is preferably enlarged or counterbored as at a3 to receive a nipple 63- on the upper side of the socket block E. The lower end of the stockA on` both sides of the distance block a is beveled or inclined inwardly and upwardly to form the inclined abutments a for the reception of the shoulders b of the bits B.

E. indicates a socket block of a jform, adapted to be inserted 'and secured in the upper endV of transverse slot a, andl saidblock is,l

position in the transverse slot a ofthe stock,

shall co-act `therewith to form a socket ar,7 for the reception ofthe tangs b ofthe bits.

The upper portion of the socket blockl E is perforated for the passage of the rod C to which the bits are attached, and said perforation is surrounded by an annular pro. jectionl or nipple e3 which enters the counterbore or enlarged mouth a5 of the bore a2 in order to support the socket block E against lateral strain.

The under lsurface e4 of the socket'blo'ck E constitutes the abutment for the upper ends'of the bittangs b, and the pendent portions e2, e2 afford a lateral support to the bit tangs, the bit tangs b, b engagingvin the axis of the stock so as to mutually support each other.

It is -to be l noted` that the rectangular shape of slot a permits of the easy machine 'finish of the walls of said slot, w ile at the same time great stren th of stockl is secured having the distance b ock a integral there-J with, and it will be also noted that by reason of the shape of said slot the tang socket af of the stock is secured by means of a block which being separable from the stock,

tangs can also be readily' and cheaply shaped\and machine finished. l v

. B, B indicate the bits or cutters/0f the uriderreamer. These bits are provided with which extend up into the socket a of' the stock when the bits are in operative position and-With upwardly and inwardly inclined shoulders b which engage the abut- 'ments as on 'the lower end lof the stock- A.

The inner faces of the tangs b of bits B are cutback as at b2 to'accommodate the distance block when the bits are in the lower or collapsed position shown in Fig. 2 vof the drawing, and the upper ends oftangs b are slotted as at b8 for the reception of the hooks v0' c pivoted on ythe spring-actuated rod C, which hooks engage pins b* extending across theslots b3.

`0, o indicate hooks pivoted on the spring-y actuated member C and adapted to engage y the pins b4, b4 in the slotted upper ends of the bit tangs b, and thus establish a flexible u connection between the bits and actuating spring o f a character which will not interfere with the tilting ofthe bits in passing.

to and from the collapsed and operative p0- sitions of said bits.

In Fig.l 7 is shown means for facilitating vthe assembling of the parts of the underreamer and for applying4 the bits to andremoving them from the stock. This means as shown comprises athreadedl stub R.

adapted to bescrewed into `the box a* of the stock A anda screw rod r which passes -through the stub R and is ada ted to engage the upper end of the mem er C when in position in the stock A. A

The several parts of the underreamer being of the character hereinbefore pointed out, said parts may be assembled as follows: The socket block 'E is inserted in the slot a' .'of stock A, and secured by screwsas indicated at e. -The spring D is placed on the rod C and the 70d and spring inserted, in the bore a2 -of the stock with the lower end of :spring D resting on the shoulder as of the bore.

The stub R is then 'screwed into box a* of the stock and the screw rod r is operated to force the member Cdown 'until its lower end projects into the socket a" of the stock A suic'iently far to permit the pivotal attachment of the hooks 0 c and member Cto be made, after which the bits B'B may be entered in the slot a of the stock, and the hooks 0 c caused to engagerthe pins I)4 in the slots b3 of tangs b. When the screw rod r is retracted, the expansion of spring vD will draw the tangs b b of the bits'B. B up into distance bloc The `stub R may then be removed from' boX a4 of the stock until such time as it may be desired to remove the bits B, B for sharpening or for replacing the same. v

The parts of the underreamer being' in the normal or operative posltlon, as shown 1n F ig. 1 of the drawing, when itlis desired to introduce the underreamer into the casing, the bits B B will be drawn down and tem` porarily secured in the position shown in Fig. 2 of the drawing,- in which condition the bits B B will be entered in the casing and the securing device removed to release the bits. The casing will retain the bits in collapsed position while the underreamer is passing therethrough, but as the bits B B escape from the lower end of the casing the expansion of spring D will cause the bits to again assume the operative position, as shown in Fig. l of the drawing.

lVhen the underreamer is to be withdrawn from the easing, the upward pull on the stock A will bring the outer surfaces of the bits into engagement with the lower end of the casing andthe bits `will be held until the up 'ard movement of the stock brings the distance block a opposite the recesses b2 b2 on the inner faces of the tangs b, whereupon the bits will collapse or assume the position shown in Fig. 2 of the drawing, in which condition the underreamer can be withdrawn through the casino'.v

' Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A slotted underreamer stock, having a distance block integral with the stock, and adapted to extend between and maintain underreamer bits in operative position and an inserted socket-block.

2. In an underreamer, the combination of a slotted stock having abutments and a distance block adapted to extend between and support the underreamer bits, said distance block integral with the stock, an inserted socket-block, and bits slidable on the stock and having tangs which enter the socketblock. s

3. In an underreamer, the combination of a slotted stoel; having a socket for the reception ot' the tangs of the bits, a distanceblock at its lower end and abutments adjacent thereto, bits slidable onthe bit stock, a spring for actuating the bits, and pivoted hooks interposed between the bits and spring for actuating the bits.

Ll. In an nnderreamer, the combination of a slotted bit stock having abutments and a distance-block integral with the stock, an inserted socket-block, bits slidable on the stock and having tangs which enter the socket-block, a spring for actuating the bits, and hooks interposed between the spring and bits.

5. In an underreamer, the combination with a stock having ar central bore, a reetangular slot extending through the stock and intersecting the bore, and a distanceblocl: adapted to extend between and maintain underreamer bits in operative position, said distance block integral with the stock, of an inserted socket block of general U- shape and provided with an annular projection or nipple adapted to enter the bore otl the stock.

In testimony whereof I affix my signature, in presence of two subscribing witnesses.

PATRICK I-I. MACK.

Witnesses G. P. RITTER, CHARLES LOWELL Howauu.

yco 

